Carl-Daniel Hailfinger wrote:
On 27.11.2007 17:45, Corey Osgood wrote:
ron minnich wrote:
On Nov 27, 2007 8:24 AM, Corey Osgood corey.osgood@gmail.com wrote:
[SPD_MIN_CYCLE_TIME_AT_CAS_MAX] = 10, /* A guess for the tRAC value */This looks like it's wrong, a normal DDR400 dimm is 0x50 or so.
[SPD_MODULE_ATTRIBUTES] = 0xff, /* FIXME later when we figure out. */0x20 for an unbuffered dimm, 0x26 for registered.
So I'm going to ask a favor. I am going from the data sheets and could not find this info. Can you look and tell me? I got lost in the numbers ...
I cheated ;) Here's a micron datasheet for a DDR400 CL3 Dimm: http://download.micron.com/pdf/datasheets/modules/ddr/DDA9C16_32_64x72AG.pdf
And what should be known as the best idiot's guide to SPD out there: http://www.simmtester.com/page/news/showpubnews.asp?num=101
I have the JEDEC datasheet on this, but I have so damn many JEDEC datasheets I simply can't figure out which one it is. The "SPD_ACCEPTABLE_CAS_LATENCIES" also should be 0x50 (5ns).
Can you add these links to the wiki, probably to a page about SPD or RAM?
Regards, Carl-Daniel
I don't have wiki access (care to help with that Ron?). The second one's already in the developer manual, but there are corresponding guides for sdram, ddr2, and ddr3 which should be added, along with more datasheet links. I'll also add links to the JEDEC docs if I can find them, I think everyone could use them for reference.
-Corey